Timing Reference High Resolution Signal B Intermittent/Erratic Pulses
The engine's computer detected unstable or flickering signals from the camshaft position sensor B, like a strobe light that keeps cutting out instead of flashing steadily. This makes the ECU unsure about precise engine timing, similar to trying to read a book with a failing flashlight.
The ECM monitors the frequency and pattern of pulses from the camshaft position sensor B, which signal exact crankshaft position for fuel injection and ignition timing. If pulse intervals are inconsistent, delayed, or missing, the ECM logs a fault. The sensor must deliver stable, evenly-spaced signals within expected timing windows.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Pulse Signal Stability | Consistent 5V pulses at regular intervals | Erratic, intermittent, or missing pulses |
| Signal Frequency | Within specification for engine RPM | Drops below or exceeds acceptable range |
Code P0379 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0379 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.